Re: List - C# Discussion Boards

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Re: Message formatting question (expires on sunday)

BoneSoft28-Jul-07 8:12

BoneSoft

28-Jul-07 8:12

Personally, I just type of paste code into a <pre /> tag. I assume code project automatically converts all line breaks into <br> tags.

Try code model generation tools at BoneSoft.com.

Re: Message formatting question (expires on sunday)

Luc Pattyn28-Jul-07 9:09

Luc Pattyn

28-Jul-07 9:09

Thanks.

Luc Pattyn

try { [Search CP Articles] [Search CP Forums] [Forum Guidelines] [My Articles] }
catch { [Google] }

List

sangramkp25-Jul-07 3:14

sangramkp

25-Jul-07 3:14

How to iterate along each and every item of a List<t>?

Re: List

Guffa25-Jul-07 3:22

Guffa

25-Jul-07 3:22

foreach (SomeType theItem in someList) {
   DoSomethingWith(theItem);
}

---
single minded; short sighted; long gone;

Re: List

PhilDanger25-Jul-07 3:29

PhilDanger

25-Jul-07 3:29

----
List<int> intList = new List<int>();
//fill the list
//...

foreach(int myInt in intList){
Console.WriteLine(myInt);
}
----
This enumerates over all integers in intList, storing them in the variable myInt inside the loop so that you can access it.

Note that you can't edit the list itself during this loop, so if you are trying to remove an element from the list you will get an exception thrown. The way around this is to make a separate list to store the elements that you want removed, then loop through those later and remove them from your original list OR, see below (looping backwards and removing elements)

----
//loops through intList and removes every 0 from the list
cont int BADVAL = 0;
for(int i = intList.Count - 1; i >= 0; --i){
if(intList[i] == BADVAL){
intList.RemoveAt(i); //removes the current index from the list
}
}
----

Re: List

sangramkp25-Jul-07 4:50

sangramkp

25-Jul-07 4:50

Hi PhilDanger,

Thanks for reply...

I have a specific problem.... I hope u will help me out

SeatEntity is a class having fields seat_id and row_id and properties SeatId and RowId. I stored the SeatId and RowId in a List<seatentity> now while iterating each and every cell of a dataGridView Control I want to iterate through each item in List<eeatentity> and comapre its values with the cells RowIndex and ColumnIndex....
Ur help will be much aapreciated

Re: List

PhilDanger25-Jul-07 5:01

PhilDanger

25-Jul-07 5:01

In your loop that iterates through the DataGridView, assume that you have two values RowIndex and ColumnIndex that point to the appropriate cell.

//this is inside the loop of the datagrid view...
SeatEntity gridSeat = (SeatEntity)gridView[ColumnIndex, RowIndex].Value;
//We did a few things here, we indexed into the gridView using the column and the row, this returns a DataGridViewCell.
//We then used the .Value property to get what is stored inside.  Since this returns an object, we cast it to the type that we stored in the grid (I'm assuming you're storing SeatEntitys).

//now we can loop through the list and compare the values
foreach(SeatEntity seat in seatList){
    if(seat.SeatId == gridSeat.SeatId){
         //do something
    }
}

Re: List

sangramkp25-Jul-07 6:32

sangramkp

25-Jul-07 6:32

Hi I am sending u the code if u can help better

SeatChartService scs = new SeatChartService();

private void Form1_Load(object sender, EventArgs e)
{
List<seatentitiy> seat = scs.GetSeats();

//dataGridView1.DataSource = seat;
dataGridView1.ColumnCount = scs.GetColumnCount();
dataGridView1.RowCount = scs.GetRowCount();
int i = 0;
int j = 0;

foreach (DataGridViewTextBoxColumn c in dataGridView1.Columns)
{
c.HeaderText = i.ToString();
i++;
}

foreach (DataGridViewRow r in dataGridView1.Rows)
{
r.HeaderCell.Value = j.ToString();
j++;
}

SeatEntitiy seobj= new SeatEntitiy();
foreach (DataGridViewRow row in dataGridView1.Rows)
{
foreach (DataGridViewCell cell in row.Cells)
{
foreach (SeatEntitiy se in seat)
{
//SeatEntity gridSeat = (SeatEntity)cell[ColumnIndex, RowIndex].Value;

seobj.SeatId = se.SeatId.ToString();
seobj.RowId = se.RowId.ToString();
if (cell.ColumnIndex.ToString() == seobj.SeatId.Substring(14) && cell.RowIndex.ToString() == seobj.RowId.Substring(12))
{
cell.Style.BackColor = Color.Green;
//MessageBox.Show(cell.ColumnIndex.ToString(),cell.RowIndex.ToString());
}
else
{
cell.Style.BackColor = Color.Red;
}
}
}
}

}

Re: List

PhilDanger25-Jul-07 6:50

PhilDanger

25-Jul-07 6:50

What's the problem with this code?

Re: help needed using gprs connection

Justin Perez25-Jul-07 3:06

Justin Perez

25-Jul-07 3:06

Wrong forum, see Mobile Development[^]

I get all the news I need from the weather report - Paul Simon (from "The Only Living Boy in New York")

Generating Unique Numbers

Jalpesh B. Patel25-Jul-07 2:55

Jalpesh B. Patel

25-Jul-07 2:55

Hi,

I would like to make an application that generates unique numbers (numerics only) in sequential order (better if this way but not compulsory).

It should be able to recover in case of a crash. i.e. if the generation crashes or system crashes, then the next time its up, it should give unique numbers only, and not repeat any number previously given. This is of utmost importance.

And if crash recovery feature doesn't involve I/O, it would be better. (e.g saving numbers to disk and stuff).

Note: Random is not mandatory, unique is.

If you have a solution to this, please help.

Thank you.

Re: Generating Unique Numbers

Colin Angus Mackay25-Jul-07 3:01

Colin Angus Mackay

25-Jul-07 3:01

Use GUIDs and convert them to numeric - it is a sequence of HEX anyway so it can be converted quite easily.

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My website

Re: Generating Unique Numbers

Luc Pattyn25-Jul-07 3:48

Luc Pattyn

25-Jul-07 3:48

Hi Colin,

this is puzzling me: I expect GUID are unique all over the universe.
They also need many bits; how can it be if a take 1 million GUIDs and convert each of them
to int, that all ints will also be unique (inside my confined process that is),
so which transformation preserves uniqueness while compressing from many to 32 bits ??

A simple hash code wont be sufficient, its only function as I understand is putting objects
into 2^32 buckets with a "good distribution".

Can you enlighten me on this ? Thanks.

Luc Pattyn

try { [Search CP Articles] [Search CP Forums] [Forum Guidelines] [My Articles] }
catch { [Google] }

Re: Generating Unique Numbers

Colin Angus Mackay25-Jul-07 4:03

Colin Angus Mackay

25-Jul-07 4:03

Guids are 128 bits. No one said anything about being constrained to 32 bits.

Re: Generating Unique Numbers

Luc Pattyn25-Jul-07 4:11

Luc Pattyn

25-Jul-07 4:11

Thanks Colin

I confused with the GUID strings, the ones used for registering a class (and filling the
registry).

Now 128-bit isnt very much, and MSDN on Guid.NewGuid says "There is a very low probability that the value of the new Guid is all zeroes or equal to any other Guid." which may not be good
enough for the OP, he really insisted on uniqueness...

Smile | :)

Luc Pattyn

try { [Search CP Articles] [Search CP Forums] [Forum Guidelines] [My Articles] }
catch { [Google] }

Re: Generating Unique Numbers

CPallini25-Jul-07 4:19

CPallini

25-Jul-07 4:19

Oh, the OP don't have to worry about it...
However, using GUIDs is not practical due to timing requiremts and 128-bit integers handling: he don't need such complexity.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Re: Generating Unique Numbers

CPallini25-Jul-07 4:15

CPallini

25-Jul-07 4:15

Your solution is simply not practical.
See Luc Pattyn one [^] for a better approach (at least IMHO).
Smile | :)

BTW you don't need to convert hexadecimal chars to obtain integers from GUIDs.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Re: Generating Unique Numbers

Colin Angus Mackay25-Jul-07 10:43

Colin Angus Mackay

25-Jul-07 10:43

CPallini wrote:
Your solution is simply not practical.

I realise this also[^]

Re: Generating Unique Numbers

Jalpesh B. Patel25-Jul-07 4:01

Jalpesh B. Patel

25-Jul-07 4:01

Converting GUID into numbers does not guarantee uniqueness... I've checked that already.

Re: Generating Unique Numbers

Colin Angus Mackay25-Jul-07 4:05

Colin Angus Mackay

25-Jul-07 4:05

Jalpesh B. Patel wrote:
Converting GUID into numbers does not guarantee uniqueness... I've checked that already.

Yes, it does. You have to translate it in to a 128bit number. You never specified you were constrained by a specific size of number. If that is the case you might want to be a bit more specific about your requirements in the future.